The HDMI Forum has announced that HDMI 2.1 is ready. The new standard significantly increases bandwidth to allow for 8K and 10K resolution as well as 4K120. HDMI 2.1 also supports variable refresh rate and finally fixes blank screens when switching mode. Full overview below.

HDMI 2.1 – the future

HDMI 2.1 was unveiled at CES 2017 in January. The interface standard has now been finalized and compliance tests can begin in Q1-Q3 2018, the organization said.

Besides support for 8K and 10K resolution as well as 4K resolution at 120fps, HDMI 2.1 supports Dynamic HDR to enable “multiple static and dynamic HDR solutions”. It features eARC that “supports the most advanced high bitrate home theater audio formats, object-based audio, uncompressed 5.1 and 7.1, and 32-channel uncompressed audio” with audio bandwidth up to 37 Mb/s for Dolby Atmos, DTS:X, and more.

- "The HDMI Forum's mission is to develop specifications meeting market needs, growing demands for higher performance, and to enable future product opportunities," said Robert Blanchard of Sony Electronics, president of the HDMI Forum.

Since the announcement in January 2017, a few new – very welcomed – features have been added, and these are perhaps some of the most exciting in the near term. Besides support for ‘VRR’ to enable variable, or adaptive, refresh rate (think FreeSync for TVs), the three new features are:

Auto Low Latency Mode (ALLM) allows the ideal latency setting to automatically be set allowing for smooth, lag-free and uninterrupted viewing and interactivity.

So, gone are the blank screens when switching between frequencies and modes on TVs. The HDMI Forum says that the new features “ensure an added level of smooth and seamless motion and transitions for gaming, movies and video”.

New 48G cable

HDMI 2.1 significantly increases bandwidth; from 18Gb/s to 48 Gb/s. To benefit from the increased bandwidth, a new cable is required. Look for the ‘Ultra High Speed’ HDMI cable. The first such cable went on sale recently.

- “Supporting the 48Gbps bandwidth is the new Ultra High Speed HDMI Cable. The cable ensures high-bandwidth dependent features are delivered including uncompressed 8K video with HDR. It features exceptionally low EMI (electro-magnetic interference) which reduces interference with nearby wireless devices. The cable is backwards compatible and can be used with the existing installed base of HDMI devices,” the HDMI Forum said.

HDMI 2.1 is fully backward compatible. The cable is new but the connectors at each end still fit existing HDMI ports.

Dynamic HDR ensures every moment of a video is displayed at its ideal values for depth, detail, brightness, contrast, and wider color gamuts—on a scene-by-scene or even a frame-by-frame basis.

48G cables Ultra High Speed’ cables enable up to 48Gbps bandwidth for uncompressed HDMI 2.1 feature support including 8K video with HDR. The cable is backwards compatible with earlier versions of the HDMI Specification and can be used with existing HDMI devices.

eARC supports the most advanced audio formats such as object-based audio, and enables advanced audio signal control capabilities including device auto-detect.